1. Field of the Invention
The present invention relates to a window shade, particular to a duet power-driven window shade.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a conventional shade 1 of a TW patent publication No. M414904 includes a first covering sheet 11, a second covering sheet 12 connected to a bottom end of the first covering sheet 11, and a controlling device 13. Wherein the controlling device 13 includes a remote control 131 emitting an external controlling signal, at least one receiver 132 receiving the controlling signal, a logistic processing unit 133 electrically connected to the receiver 132, a first controlling module 134 electrically connected to the logistic processing unit 133, and a second controlling module 135 electrically connected to the logistic processing unit 133. The receiver 132 includes a first receiver 1321 and a second receiver 1322. The first controlling module 134 has a first positioning member 1340, a first motor 1341 electrically connected to the first positioning member 1340, at least one first roller 1342 driven by the first motor 1341, and at least one first rope 1343 disposed on the first roller 1342 and connected to the first covering sheet 11. The second module 135 has a second positioning member 1350, a second motor 1351 electrically connected to the second positioning member 1350, at least one second roller 1352 driven by the second motor 1351, and at least one second rope 1353 disposed to the second roller 1352 and connected to the second covering sheet 12.
Referring to FIGS. 1 and 2, in order to descend or roll up the first covering sheet 11, a first up button A, a first down button B, and a stop button C of the remote control 131 can be timely pressed to create respective controlling signals adapted to the first covering sheet 11. The first receiver 1321 thence receives and transmits the controlling signal to the logistic processing unit 133. The logistic processing unit 133 determines the controlling signal and forwards it to the first positioning member 1340 so that the first positioning member 1340 is able to control a rotating direction and a revolution number of the first motor 1341. The same operating mode for controlling the second covering sheet 12 is also described. Press a second up button A′, a second down button B′, and a second stop button C′ of the remote control 131 to create respective controlling signals adapted to the second covering sheet 12. The second receiver 1322 receives and transmits the controlling signal to the logistic processing unit 133. The logistic processing unit 133 determines the controlling signal and forwards it to the second positioning member 1350 so that the second positioning member 1350 is able to control a rotating direction and a revolution number of the second motor 1351. The first controlling module 134 and the second controlling module 135 are respectively connected to the first covering sheet 11 and the second covering sheet 12, so the user uses the remote control 131 to descend or convolute the covering sheets 11, 12, separately.
The convention shade 1 may descend or roll up the covering sheets 11, 12, whereas, in view of the second covering sheet 12 connected to the bottom end of the first covering sheet 11 and the isolated controlling mode of the remote control 131, the shade has to arrange two separate receivers 1321, 1322 to receive different controlling signals for actions. Therefore, there may be problems while rolling the covering sheets 11, 12 up completely, described as follows:
1. To control the rolling movement of the second covering sheet 12 before controlling the rolling movement of the first covering sheet 11, the rolling movement of the first covering sheet 11 does not act until the second covering sheet 12 completes its rolling action by pressing the button and the user further presses the button to activate the first covering sheet 11, which however consumes time and incurs inconvenience. Further, the first covering sheet 11 is subjected to the propelling motion of the second covering sheet 12 from downward to upward during the rolling action, with the result that the first rope 1343 gets loose when the first roller 1342 is not prepared to be rotated. In this manner, when the first covering sheet 11 is ready to be rolled up, the loose first rope 1343 may be entangled and cannot be convoluted smoothly. Thus, the disorderly first rope 1343 causes a malfunction and easily affects the following rolling and descending operations.
2. To control the rolling movement of the first covering sheet 11 up before controlling the rolling movement of the second covering sheet 12, the rolling movement of the first covering sheet 11 propels the second covering sheet 12 upward and causes the second rope 1353 of the second covering sheet 12 to become loose. Further, some impatient users may conduct a rolling movement of the second covering sheet 12 directly, while the first covering sheet 11 has not been completed rolled up. In view of the second covering sheet 12 subjected to the rolling movement of the first covering sheet 11, the second rope 1353 gets loose more easily and becomes failed to be convoluted round the second roller 1352 entirely. Thus, the disorderly second rope 1353 causes a malfunction and affects the following operation.
3. Since the remote control 131 is operated by controlling the covering sheets 11, 12 respectively, the user cannot press to activate the two controlling signals at the same time. This design causes the rolling movements of the first covering sheet 11 and the second covering sheet 12 unable to be operated concurrently and the separate first receiver 1321 and the second receiver 1322 unable to perform the concurrent receiving actions, which causes a time differential. As a result, the rotating speeds of the first roller 1342 and the second roller 1352 can not be identical owing to the time differential. Adversely, the ropes 1343, 1353 get loose easily, both of which also cannot be entirely convoluted round the rollers 1342, 1352 while completing the rolling movement of the covering sheets 11, 12. In the next time of rolling or descending actions, the disorderly ropes 1343, 1353 may malfunction and decrease the operating effect.